1. Field of the Invention
The present invention relates to a grinding machine for grinding workpieces, in particular cams, and to a grinding wheel holder and a method for grinding cam sets.
2. Discussion of Background Information
Grinding machines of this type are known, for example, from the brochure “CamGrind—Produktionsloesungen fuer das Schleifen von Nockenwellen” [CamGrind—production solutions for the grinding of camshafts] from Studer Schaudt GmbH, Stuttgart, dated October 2006. In this publication, for example, the model “CamGrind S” has a grinding device which consists of a large grinding wheel and of a small grinding wheel and is conceived in particular for grinding camshafts. With the large grinding wheel, first of all the cams are pre-ground and the bearing seats machined with high productive capacity, whereas the small grinding wheel serves to finish grind the cam shapes or also to grind the bearing seats. For the machining of the camshaft, said camshaft is arranged on a workholding device which has a work headstock on one side, said work headstock setting the camshaft in the desired rotation about its longitudinal axis, and a tailstock on the other side, said tailstock ensuring that the camshaft is always oriented and centered during the machining. Compared with these, as a rule stationary, components of the workholding device, the grinding wheels or the corresponding grinding spindles are movable relative to the camshaft within the x-z plane.
Where axes or directions x and z are referred to above or below, this always means the two axes which define the plane which forms the machine bed. In this case, the z-axis extends parallel to the longitudinal extent of the workpiece, here, for example, the camshaft, and the x-axis extends as an axis perpendicular thereto, which therefore corresponds to a movement of a tool towards or away from the corresponding workpiece from the side. Furthermore, a direction perpendicular to the x- and z-axes is designated as y-axis or y-direction. It consequently runs perpendicularly to the machine bed.
The grinding of the cams directly on the shaft is carried out for the sake of accuracy so that the cams are formed exactly with respect to the shaft. Compared with this established method, the grinding of individual cams is being increasingly used, since manufacturers of camshafts have in the meantime been successful in being able to join the individual cams to a shaft in a very exact manner. In this case, the exact grinding of the individual cams takes place individually or as groups of a plurality of cams which are usually machined on a work fixture, as a rule a mounting arbor in a grinding machine.